Archive for: 400 f/4

Patent: 400 f/4, 300 f/4, 200 f/5.6

New Lens Formula Patents
A new 400 f/4L IS non-DO would probably be a very welcomed lens. However, it will probably depend on the price of the 200-400 f/4L IS 1.4x ($8000+ I predict) as to whether or not it ever sees the light of day. The 200 f/5.6 is a strange one.

Patent Publication No. 2012-22105

  • 2012.2.2 Release Date
  • 2010.7.14 filing date

Example 1

  • 392.00mm focal length
  • Fno 4.12
  • 3.15deg half angle of view.
  • Image height 21.64mm
  • Length 279.32mm lens
  • BF 64.82mm
  • 15 sheets of 12 group configuration
  • An aspherical surface
  • Inner focus
  • Telephoto ratio 0.71

Example 3

  • 200.00mm focal length
  • Fno 5.77
  • 6.18deg half angle of view.
  • Image height 21.64mm
  • Length 180.00mm lens
  • BF 54.98mm
  • 6 lenses in 5 groups configuration
  • Telephoto ratio 0.90

Example 4

  • 294.00mm focal length
  • Fno 4.14
  • 4.21deg half angle of view.
  • Image height 21.64mm
  • Length 239.85mm lens
  • 14 images in 9 groups configuration
  • An aspherical surface
  • Inner Focus
  • Telephoto ratio 0.815
  • Telephoto lens
  • Stretch the focal length, and miniaturized, on-axis chromatic aberration and lateral chromatic aberration occurs
  • Tele photo lens type refers to the overall length is shorter than the focal length
  • And telephoto ratio refers to the value obtained by dividing the focal length the total length
  • Canon’s patent
  • Using the lens refractive index distribution

 Source: [EG]

cr

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